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Oxytocin will not work on breast resulting on milky discharge if the glands were not "prepared" by prolactin. It's like trying to squeeze empty balloon - nothing goes out.
this makes sense to me, X cannot be Km!! because if it was Km then line B would be showing a "competitive inhibitor" effect, which cannot be the case since they state that the enzyme activity increases to normal after B6 administration so it favors the reaction instead of decreases it. I got this one wrong of course, too tricky for me!
Why is it regurg instead of stenosis?
Vague question requires a lot clinical reasoning.
mitral regurgitation: holosystolic murmur( this cv: midsystolic), enlarged LA, LV
Mitral stenosis: diastolic murmur, enlarged LA, normal LV.
only best explanation I can think of: early stage Mitral regur, that's why the murmur is not holosystolic but midsystolic and LV still adequately handle the situation
@hpsbwz it's regurgitation because the murmur is SYSTOLIC, when the mitral valve is not supposed to make any sound. mitral valve leaks in systole, which causes blood to back up, which causes the left atrium to work harder and eventually hypertrophy.
Mitral stenosis would be a DIASTOLIC sound, which is when the left atrium normally contracts.
I'm still confused as to why mitral regurg has an enlarged left atrium. Are we supposed to think that it was mitral stenosis for a time, the high LA pressure led to hypertrophy, and then became mitral regurg? That's how it works in rheumatic fever, right?
I agree that mitral regurgitation is a holosystolic murmur heard best heard over the apex. However, with the murmur being found in the mitral valve area of auscultation it was the only answer choice that could result in LA enlargement and normal LV. Ruled out mitral valve stenosis since it is a diastolic murmur.
@themangobandit I believe mitral regurg could cause an enlarged left atrium from the increased amount of blood flooding back into the left atrium with each systole causing increased pressure on the wall.
why is LV size normal? doesnt cause MR cause increased preload and overload over time leading to enlarged LV?
This patient does not undergo a water deprivation test
Compulsive water drinking or psychogenic polydipsia is now increasingly seen in psychiatric populations. Effects of increased water intake can lead to hyponatremia causing symptoms of nausea, vomiting, seizures, delirium and can even be life threatening if not recognized and managed early.
Just wondering why it in not resistance to ADH action of vasopressin
because he would be hypernatremic with no ADH. can't resorb any water
low osm/urine, low os/plasma => psychogenic polydipsia
In this question the pt had a normal urine osm (80) a low urine osm would be <50mosmol/kg.